sql - SQL - 加入 2 个查询？

Question

我有两个查询：

Select trunc(create_dtime) as Day, Count(Player_Id) as New_Users
From Player
Where Trunc(Create_Dtime) >= To_Date('2012-Jan-01','yyyy-mon-dd')
Group By Trunc(Create_Dtime)

和

Select trunc(create_dtime) as Day,Count(Player_Id) as Retained_Users
From Player
Where Trunc(Create_Dtime) >= To_Date('2012-Jan-01','yyyy-mon-dd')
And Trunc(Init_Dtime)  >= Trunc(Sysdate) - 7
Group By Trunc(Create_Dtime)
Order By Day Asc

每天都有一个价值，我想将这两个查询连接在一起，所以我只有一个查询而不是两个。

Answer 1

您不需要在那里加入：

SELECT
  TRUNC(CREATE_DTIME) AS DAY,
  COUNT(PLAYER_ID) AS NEW_USERS,
  COUNT(CASE WHEN TRUNC(INIT_DTIME) >= TRUNC(SYSDATE) - 7 THEN PLAYER_ID ELSE NULL END)     AS RETAINED_USERS
FROM PLAYER
WHERE TRUNC(CREATE_DTIME) >= TO_DATE('2012-Jan-01','yyyy-mon-dd')
GROUP BY TRUNC(CREATE_DTIME)
ORDER BY 1

Answer 2

这只是一个内部联接，除非您想在其他查询中包含不匹配的结果。否则，您只需使用：

SELECT * FROM query1 INNER JOIN query2 ON query1.Day=query2.Day

我应该注意这是 MySQL 的语法，我没有意识到您将其标记为 Oracle。如果不完全相同，语法可能会相似，但我从未使用过 Oracle。

Answer 3

我明白了，我只是忘记标记列。

Select one.Day, one.New_Users, two.Retained_Users
From
(
Select trunc(create_dtime) as Day, Count(Player_Id) as New_Users
From Player
Where Trunc(Create_Dtime) >= To_Date('2012-Jan-01','yyyy-mon-dd')
Group By Trunc(Create_Dtime)
) One
Inner Join 
(
Select trunc(create_dtime) as Day,Count(Player_Id) as Retained_Users
From Player
Where Trunc(Create_Dtime) >= To_Date('2012-Jan-01','yyyy-mon-dd')
And Trunc(Init_Dtime)  >= Trunc(Sysdate) - 7
Group By Trunc(Create_Dtime)
Order By Day Asc
) Two On One.Day=Two.Day
Order By 1